Pictures brought to life by living photo film

24 November 2005

Scientists have grown a photography world first: ultra-high-definition 'living photographic film'. It's made from specially engineered bacteria that can react to red light.

Antenna takes a closer look...

This story was published in Nature on 24 November 2005.
How does it work?
The living film is made from a lawn of E. coli bacteria. Each tiny bug can be light or dark, just like the pixels that make up a digital photograph. How does each bug know which to be?

The scientists have used their clever technique to 'draw' a little monster in the lawn of E. coli bacteria growing in this petri-dish.

Image: Aaron Chevalier

The living film is made from E. coli bacteria like these.

Image: Eric Erbe/Christopher Pooley/USDA

E. coli cells can't usually 'see', so American bacteria experts pinched a light-sensing gene from blue-green algae and popped it into the E. coli cells using genetic engineering.
That wasn't the end to the scientists' clever tricks...
'We hooked up E. coli's new light-sensing gene to a pigment-producing gene called LacZ,' says Chris Voigt from the University of California research team. 'This gave us a "pigment control switch"... and a new way to capture black-and-white images using live organisms.'

Chris Voigt, bacteria expert, University of California at San Francisco

Image: Aaron Chevalier

Image: Aaron Chevalier

In the dark, the bacteria's pigment production carries on at full speed, creating a black speck on the film. But in the light it grinds to a halt, leaving a light spot. The smart cells even respond to varying levels of light, grading their pigment production to create shades of grey.
To test their new technique, the scientists grew dense lawns of E. coli cells. Then they exposed this living photographic film to intricate patterns of light using stencils and black-and-white transparencies.
Result! The E. coli photographs are impressively high-definition - the equivalent of up to 100 megapixels per square inch. That's an amazing eight times more detail than today's best digital cameras.

Image: Aaron Chevalier

What's the future for E. coli film?
If you're unsure that living photographic film could replace high-street happy-snapping kit or hi-tech digital cameras, don't worry. The bugs' designers have more creative applications in mind...

'Our pictures show that scientists could use light to control how bacteria behave. Bacteria are important for many areas of science from materials to therapeutics. So for example we could put light sensors - like the ones we tested in bacteria - into stem cells, then use light to help build whole organs,' says Chris Voigt.
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